A conventional Western-style toilet has a simple structure, in which a toilet seat and a toilet cover are pivotally supported so as to rise and fall on the top face of a rim on the back side of a toilet bowl main body. In recent years, however, a toilet seat device with a function of cleansing the bottom with warm water or a heated toilet seat device has been installed in the toilet. In such a toilet, the toilet seat and the toilet cover are pivotally supported by a container case, which is disposed in the top surface of the rim. As the container case contains electrical components and the like for operating and controlling the cleansing function with warm water and the function of heating the toilet seat, the container necessarily protrudes from the top face of the rim. As a result, the pivotally supported positions of the toilet seat and the toilet cover are higher than those of the conventional Western-style toilet.
When the pivotally supported positions of the toilet seat and the toilet cover are high, as described above, it becomes difficult to keep the toilet seat and the toilet cover in raised positions in a case where a man urinates. Thus, there is a possibility that the toilet seat and the toilet cover fall down during urination.
To prevent such inconvenience, in the toilet having the warm-water cleansing toilet seat device, a lifting and lowering control unit is fixed in the container case of the debit toilet seat device. In the lifting and lowering control unit, a torsion spring for urging the toilet seat and the toilet cover in a lifting direction is integrated into an automatic lifting and lowering device or a damper device. The automatic lifting and lowering device automatically lifts and lowers the toilet seat and the toilet cover by a user detection signal, a remote control operation, or the like. The damper device is provided to gently lower the toilet seat and the toilet cover. Such structure makes it possible to lightly lift the toilet seat and the toilet cover, and securely keeps the toilet seat and the toilet cover in a lifted state (a state in which the toilet seat and the toilet cover are raised) while preventing the toilet seat and the toilet cover from being undesirably lowered.
By the way, the scene of product development aims to efficiently produce a product group with wide variations in order to meet various market needs. Therefore, products with several variations are often developed based on, for example, one type of basic specifications in accordance with various requirements of a customer.
Accordingly, also in the automatic lifting and lowering devices and the damper devices for the warm-water cleansing toilet seat device, it is necessary to develop various devices corresponding to different self weight torque properties of a plurality of types of toilet seats and toilet covers in different product variations. Thus, in the automatic lifting and lowering device, products with many variations are developed by, for example, increasing torque of a drive motor, varying a speed reducing ratio of a gear in a drive system, or varying the specifications of the torsion spring. The damper devices are also developed in accordance with the different product variations by, for example, increasing and decreasing the capacity of a damper chamber, or varying the specifications of the torsion spring.
Thus, the types of parts increase in accordance with an increase in the product variations, so that not only huge manufacturing cost and management cost are required, but also a long period of time is needed for the manufacturing of the parts. An increase in the variations also increases assembly cost and management cost during manufacture.
In the conventional warm-water cleansing toilet seat device, the torsion spring for urging the toilet seat and the toilet cover to the lifting direction is provided in the automatic lifting and lowering device or the damper device. Thus, these devices necessarily become large due to space for attaching the torsion spring. This is one of the hindrances to the weight reduction and size reduction of the warm-water cleansing toilet seat device.
The present invention aims to solve the foregoing problems. An object of the present invention is to provide a relatively small lifting and lowering device for a toilet seat or toilet cover which can stably hold the toilet seat or toilet cover in a raised position, and achieve commonality of structural parts in accordance with the magnitude of self weight torque of the toilet seat or toilet cover, and to provide a transmission unit for composing the lifting and lowering device.